Spring chucking device



Nov. 27, 1951 J. MAzzoLA 2,576,350

SPRING cHUcxING DEVICE;

Filed NQv. 24, 1947 I5 Sheets-Sheet 1 Nov. 27, 1951 J, MAZZOLA 2,576,350

SPRING CHUCKING DEVICE Filed Nov. 24, 1947 5 sheets-sheet 2 N0V 27, 1951 J. MzzoLA 2,576,35Q

SPRING GHUCKING DEVICE Filed Nov. 24, 1947 3 Sheets-Shea?1 3 INVENTOR! Patented Nov. 27,r 1951 UNITED STATES PATENT GFFICE SPRING CHUCKING DEVICE Joseph Mazzola, Washington, D.C.v l Applica/.tion Ngmber 24, 1947, serial No. 787,836 I (ci. 279-6) 3'Claim's.

kThis invention relates to spring chucking'devices particularly for use inV connection with chucks in machining operations.

YIn the use of chucks and similar Achucking devices on lathes and other'machines, as, for example, in the common type geared scroll-chuck such Yas the commonly employed three jaw chuck, after use for some time there'is excessivewear so that the rwork piece held inA such rchuck runs in an untrue manner Withresultant unsatisfactory machining of the workpiece. Under such circumstances and theyjfrequently arise even after relatively short use of chucks, the machinistiinds it difficult-to compensate for'such untruerotation and manipulation of the chuck and Work piece to make it run true under these circumstances becomes a tedious, time-consuming operation.

Among the objects of the present invention is the production of a tool or chucking deviceuwhich eliminates and compensates for any untrue rotation in such chucks. i v

Other objects include a tool for these purposes which permits easy and ready adjustment for centering the work piece to be machined.

LStill further objects include such tools' or chucking devices which may be easily and feconomically manufactured. y

Still further objects and advantages of the present invention will appear from the more detailed description set forth below, it being understood that such more detailed description is given by way of illustration and explanation only, and not by way of limitation, since various changes therein may be made by those skilled in the art without departing from the scope yand spirit of the present invention.

In connection with such more detailed description, there is shown in the accompanying drawings, in

Figure 1, a front elevationofa three rjaw chuck carrying the assembled tool of the present invention; in t Figure 2, a side elevation of the deviceof Figure l, partly in section; in

Figure 3, an exploded view in perspective of the chuck and the elements of the tool or spring chucking device of the present invention; in

Figure 4, a sectionon the line 4-4 of Figure 2; in

Figure 5, a sectionv on the line 5--5 of Figure 2; in y Figure 6, a front elevation of the eccentric split tube element of the device; in

Figure 7, a rear elevation of the parts shown `in Figure 6; in

In accordance with the present invention, a tool or spring chucking device is supplied which enables ready adjustment for centering material or work pieces to be machined, to eliminate and compensate for any untrue rotation in a chuck,

t by making such tool from a multiplicity of telescoping tubular members, some of which are eccentric, so that the several telesccping parts may be adjusted with respect to each other to compensate for any untrue rotation of the material or V,work piece to be machined. As shown in the drawings, illustrating the chuck by the commonly used three jaw chuck C having jaws J, the assembled toolr T is shown in position in the chuck in Figure 1 and in section in Figure 2. The tool consists of an outer split eccentric sleeve I having the split or opening 2 therein, to supply resiliency and flexibility to such sleeve I. The circumferential surface 3 and inner wall 4 of the sleeve I are cylindrical surfaceson eccentric axes, so that at one point 5 of the sleeve I, the wall thickness is a minimum while at the opposite point 6, the wall thickness of the sleeve I is a maximum. The outer diameter of the sleeve I is made so that it may be readily gripped in the jaws J, of the chuck C, and by rotating the sleeve I within the jaws J of the chuck C, the eccentricity of the sleeve I may be made to compensate to a certain extent for any eccentricity of these jaws J.

Within the sleeve I, an eccentric split tube 'I is provided, the outer diameter of the tube I being of such size as to fit snugly within the sleeve I but to be rotatable therein prior to final tightening of the jaws J. The tube 1 is split as shown at 8 to give greater resiliency and flexibility thereto. The circumferential surface 9 and inner" wall I0 of the split tube 1 are cylindrical surfaces on non-concentric axes so that the split tube 'I is also eccentric. On one end of the split tube 'I a flange I I is provided having a knurled periphery I2 enabling the tube 'I to be readily positioned and adjusted within the sleeve I. In order to give sufiicient resiliency and flexibility to the tube 1, longitudinal grooves I3, I3 may be provided in the flange I I and the tube 1 as shown at I 4. The grooves I3, I3 and split 8 may desirably be placed at from each other to provide substantially uniform flexibility in the sleeve 1. The tube 'I may be provided with an enlarged bore I6, to accommodate the larger size collets in a manner to be described presently, the bore defined by the Wall I serving to accommodate the smaller range of collets.

The sleeve I and tube 'I may be readily assembled together with the tube I fitting snugly but rotatably within the sleeve I and the latter placed in the jaws J of the chuck C'. Rotation of the tube 'I within the sleeve I, due to the eccentric axes of the wall 4 and surface 9 enables ready adjustment of the parts to provide true concentricity with the headstock axis of the'. Y

lathe or other machine tool to which the devicel may be applied. While the sleeve l and tube I may be used for reception of thematerial or work piece to be machined, in order to permit ready use with work pieces of varying diameters, a series of collets may be provided, the bores of the collets being of varying sizes. Each collet may take the form of a cylindrical split tube such as the tubular member i1 adapted to t snugly but rotatably within the tube l, the outer face and inner wall ofthe tube being concentric cylindrical surfaces. The collet II is provided with a slot I8 to give resiliency andflexibility. At one end, the-collet may be provided with a ange I9 having a knurled periphery 20. Longitudinal grooves 2l, 2l may be provided in the flange I9 and collet l? in order to give the necessary resiliency vand flexibility thereto. The slot U grooves 2i, 2I are desirably arranged at equi distant points about the cross-section of the collet I'I, -as for example, 120 apart. The collet may be readily inserted within the tube 1, and where an enlarged bore I6 is provided inthe tube 'I, the outer diameter of the collet II will be of such size as to fit snugly but rotatably within such enlarged Abore Iain the sleeve the collet being pushed inwardly until it rests against the shoulder I of the tube 1.

The collet I'I is adapted to receive the material or work piece M on which the machining operations are to be performed. Since work piecesor material to be machined may vary substantially in diameter, a series ofcollets Il are provided having'inner diameters y22 of varying sizes, all of which will fit Within the tube l, but which due to the varying sizes of openings 22 in the collets,enable the device to be employed with work pieces M of varying diameter. Thus an 'entire set may be produced and sold as a kit as illustrated in Figure 10, where acontainer T of any usual type may be provided to hold a set of elements including a split eccentric sleeve I, a split eccentric tube I, and a series of collets II of varying sizes, the sizes of the openings 22 `in the collets I1 being provided in regular decreasing diameters.

The use of the tool of the present invention will appear from what has been set forth above in the description of the elements and their relation. The sleeve I, tube 'I, and collet I'I when the latter is employed as is most desirable, are assembled together one within the other and placed within the jaws of the chuck while the latter are open sufficiently, and the work piece M inserted within the collet II. The parts are then manipulated and the eccentricity of the sleeve I and tube 'I permit adjustment of the IS and longitudinal' parts with respect to each other and with retained. A true centering eiect is readily secured in this way despite the fact that the chuck may, due to wear, run untrue if used without the present invention. The elements of the tool of the present invention are readily produced by machining operations, from any desired stock material such as iron, steel, brass, etc. The free springing action of the parts enables ready assembly and use of the device. Where a series of collets of varying size openings are employed, they may have any desired dimensions, as for example, running from als inch in diameter to 1 inch in diameter through regular gradations of #g inch, or larger or smallerdiameters may be employed as desired. Having thus set forth my invention, I claim:

. 1. -A Vchucking device comprising a first split sleeve member, the circumferential and inner wall surfaces being eccentric with respect to the longitudinal axis thereof, a second split sleeve member rotatably received within said first sleeve member, the circumferential and inner wall surfaces 'of said second sleeve member being eccentric with respect to each other, and a collet comprising a split sleeve received .within said second sleeve member and having a longitudinal bore and a concentric outer surface whereby said i'lrst sleeve member may be clamped in the jaws of a chuck thus clamping a work piece in said collet, and the concentricity of Vsaid work piece with respect to the true center of said chuck being adjusted by relative rotation between said rst sleeve member and said chuck and between said iirst and second sleeve members to compensate for wear in said chuck and accurately center said work piece. v

2. A chucking device comprising a first split sleeve'member, the circumferential and inner wall surfaces being eccentric with respect to the lcngitudinal axis thereof,.a second split sleeve member rotatably received within said rst sleeve member and having an enlarged kr'iurled flange, a plurality of angularly spaced grooves in said ange and said second sleeve member to impart flexibility thereto, the circumferential and inner .wall surfaces of said second sleeve member being first sleeve member and said chuck and between said iirst and second sleeve members to compensate for wear Yin said chuck and accurately center said workpiece said knurled flange facilitating such adjustment. Y

3. 4A chucking device comprising a rst split sleeve member, the circumferential and inner wall surface being eccentric with respect to the longitudinal axis thereof, a second split sleeve member rotatably received withinsaid rst sleeve member and having an enlarged knurled iiange, a plurality of angularly spaced grooves in said ange and said second sleeve member to impart flexibility thereto, the circumferential and inner wall surfaces of said second sleeve member being eccentric with respect to each other, an enlarged bore in one end of said second sleeve member, the wall of said enlarged bore being eccentric with respect to the circumferential surface of said second sleeve, and a vcollet comprising a split sleeve received within said second sleeve member and having a longitudinal bore and a concentric outer surface' whereby said rst sleeve member may be clamped in the jaws of a chuck thus clamping a work piece in said collet and the concentricity of said work piece with respect to the true center of said chuckrbeing adjusted by relative rotation between said rst sleeve member and said chuck and between said first and second sleeve members to compensate for wear in said chuck and accurately center said work piece. said 10 2,420,067

knurled ange facilitating such adjustment.

JOSEPH MAZZOLA.

REFERENCES The following references are of record in the le of this patent: l;

UNITED STATES VPATENTS Number Name Date 1,125,780 Waite Jan. 19, 1915 1,189,926 Ellis July 4, 1916 2,284,394 Klein May 26, 1942 Crozier May 6, 1947 FOREIGN PATENTS Number Country Date 26,860 Denmark y Nov. 8, 1920 

